Refractory metal forming die



Feb. 7, 1967 J. H. CHATTIN ETAL REFRACTORY METAL FORMING DIE Filed NOV. 1, 1963 JOHNNY E. HAYSTRICK RAY A. LEIDY ATTORNEYS United States Patent tfice Patented Feb. 7, Th6? 3,302,439 REFRACTORY METAL FQRMHNG BEE John H. Chattin, 9318 Broadview Road, Breeksville, @hio 44141; John C. Laughlin, 42 i Anne Drive, Berea, @hio 44017; Johnny E. Haystrick, 5763 W. 46th Sta, liarma, @hio 441%; and Ray A. Leidy. 6965 Parma Paris Eli/11., Patina Heights, @hio 44129 Filed Nov. 1, 1963, Ser. No. 32%,97? 4 Claims. (Cl. 72-642) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The invention relates generally to metal working equipment and more particularly to a heated bottom adjustable die for forming refractory metals.

The space age has increased the need to form materials of refractory and super alloys. These materials include titanium, tungsten and nickel base alloys. It is a basic concept in metal forming that permanent deformation may be introduced in a workpiece by imposing a force above the yield strength of the material. This induces a permanent strain or deformation which causes the workpiece to maintain the contour which is given to it. However, in forming many of the aforesaid materials many difficulties have been encountered and nonuniformity of results have occurred. A problem which exists is the breakage or cracking of the material workpiece during forming. This is due in part to the inherent brittle nature of some of the aforesaid materials. Further, it is necessary in forming a refractory or super alloy to uniformily heat the workpiece thus lowering the yield point to where permanent plastic deformation can be obtained without elastic deformation. For most refractory and super alloys this temperature is anywhere between 400 and 2500 F. By increasing the temperature, the compressive stress necessary to initiate permanent plastic deformation is decreased together with .the probability of there being any elastic deformation occurring. Consequently, a more uniform end product with a precision contour can be achieved in an ordinary press eliminating many hours of Work. Thus, in any type of fabrication where precision work is to be performed a metal forming apparatus must be used which can accept various types and sizes of refractory and super alloy workpieces and be capable of heating the workpieces to temperatures up to 2500 F. before form- In heating the aforesaid materials to high temperatures beyond 1000 F., resistance type heaters have been used extensively. These heaters have exhibited short lives while producing relatively low temperatures. Consequently, it is diflicult with any reliability to uniformly heat metal workpieces to a temperature beyond 1600 F. Therefore, a problem exists in heating the aforesaid materials to a temperature at which they can be formed.

Another problem which exists in high temperature metal forming apparatuses is the ability to change and adjust the dies therein. Therefore, there exists a need for greater utility whereby refractory and super alloys can be formed into a multitude of geometries without the need for extensive retooling.

Accordingly, an object of the invention is to provide a new and improved apparatus for forming refractory and super alloy materials.

Another object of the instant invention is to provide a new and improved apparatus having the capability of heating uniformly refractory and super alloys to temperatures up to 2500 F.

Still, another object of the instant invention is to provide for an alloy forming apparatus which is capable of forming refractory and super alloys with the minimum of hand working.

Briefly, in accordance with one embodiment of this invention these and other objects are obtained by placing a refractory work piece in an apparatus having replaceable work surfaces which are bottom dies. These bottom dies are supported by a base in the center of which is connected a manifold capable of receiving a fuel-oxidant mixture through a plurality of burners attached thereto extending the length of the die. The burning of the fueloxidant mixture at the burner tips keeps the workpiece hot during forming, and produces the desired elevated temperatures in the workpiece. The base with the lower die thereon has a tongue attached thereto which fits into the vice jaws of a press brake. The workpiece to be formed is placed on the lower dies. The upper portion of the press brake is fitted with a top die which can be of variable diameter and/ or shape. The fuel-oxidant mixture ignites when reaching the burner tip. By regulating the fuel-oxidant mixture through the manifold temperatures as high as 2500 for forming the material can be reached. The top die is forced into contact with the metal piece until the desired contour is obtained. The top die is removed and the formed metal workpiece is allowed to cool to room temperature.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

F IG. 1 is an isometric view of the invention in cross section with the workpiece therein.

FIG. 2 is a fragmentary side view of the burner assembly.

FIG. 3 is a fragmentary side view of the top die, bottom die, and workpiece before forming.

FIG. 4 is a fragmentary side view of the top die, bottom die and workpiece during the forming process.

Referring now to the drawings wherein like reference characters designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof whereon the present invention is shown as consisting essentially of a refractory or super alloy work piece it supported on a pair of replaceable bottom dies 12. The replaceable bottom dies 12 are of a solid rectangular shape which can be made out of a high alloy steel having on one end thereof a round 14 of a preselected radius. The bottom dies 12 have therein cooling chamhers in extending the length of the dies to maintain the dies at a constant temperature by passing through the cooling chamber a cooling fluid which for reasons of economy can be water. By maintaining an adequate flow of water therethrough, the temperature of the dies 12 can be maintained within 200 F. of room temperature whereas the workpiece Jill is maintained at temperatures up to 2500 F. The replaceable dies .12 are supported and positioned centrally by a pair of first supports 13. The supports 18 are rectangular in shape and can extend in length beyond that of the dies 12. On the top 2t] and one side 22 of supports 18 there are a pair of grooves 23 diametrically opposed consisting of a side 24 and a bottom 26 whereby the dies 12 fit into the grooves. A plurality of cooling chambers 28, through which a cooling fluid is passed, extends through the supports 13 to maintain a constant temperature throughout the supports 18 and, further, cools the dies 12 by conduction. Herein, again, water can be used as a cooling fluid. The supports 18 are rigidly fixed onto a plurality of ribs 30 and are supported thereby. The ribs 30 are rigidly attached to a first base 32 and are so positioned so that convection currents can pass between the ribs 3% fur ther cooling the supports 18 and the dies 12. The cooling of the supports and dies prevents warping thereof. Positioned between the ribs 30 on first base 32 are adjusting slots 34 extending through first bases 32. First bases 32 rest on a second base 36. Aligned with the adjusting slots 34 in second base 36 are threaded holes 33. A"- justing bolts 4% are inserted in each of the threaded holes 38 through adjusting slots 34. A washer 4-2 is disposed between the bolt head 44 and the first base 32. The distance between the dies 12 can be adjusted by moving first bases 32 either toward or away from each other. The adjusting slots 34 guide these bases along the adjusting bolts 40. When the desired distance between the dies are reached the adjusting bolts 4t) are tightened, rigidly fixing the distance between them.

Referring now to FIG. 2, there is shown centrally disposed in the second base 36 a slot having a pair of sides 48 perpendicular to a bottom St, to contain a burner bar 52. The burner bar 52 which can be made out of brass extends the length of the second base 36 and has contained therein a cooling manifold 54- in the lower portion thereof and in the upper portion thereof a fueloxidant manifold 56. On the top 58 of the burner bar 52 there is contained a plurality of threaded holes 6t) extending to the depth of the fuel-oxidant manifold 56. In each of the threaded holes as there is inserted a plurality of threaded plugs 62 extending in each of the threaded holes of} to the depth of the fuel-oxidant manifold d and protruding from the top 58 of the burner bar 52 whereby a burner tip 64 having an inner threaded diameter is screwed to the top of the thread plug 62. Centrally located in and extending through the plug 62 and burner tip 64 is a hole 68 through which the fueloxidant mixture passes from the manifold 56 and ignites at the end 70 of .burner tip 64 forming a flame 72 (see FIG. 1). The energy liberated from the combination of the fuel-oxidant mixture heats the workpiece It? to the desired temperature. The cooling manifold 54 not only maintains a low temperature in the burner bar 52 but prevents pre-ignition of the fuel-oxidant mixture flowing in the fuel-oxidant manifold 56. The combination of the burner bar 52, the cooling manifold 54, fueloxidant manifold 56, the threaded plug 62 and the burner tip 64 will hereinafter be referred to as the burner assembly 73.

On the bottom 74 of the second base 36 there is a tongue 76 of rectangular cross section extending the length of the base 36. In operation the tongue '76 inserts in a conventional vice clamp assembly '78 of a conventional press brake (not shown in figures).

Referring again to FIG. 1, centrally disposed with respect to the burner assembly 66 and the replaceable dies d2 is a top die 80. The top die 80 can be of any geometric shape and length which depends on the size of the workpiece It}. The top die 80 is disposed between holders 82 and centrally attached in holes 84 in the bottom thereof. The top 86 of the holder 82 has disposed thereon a grooved tongue 88 capable of insertion in the upper end of the brake press (not shown) by a conventional clamp combination 90 attached to the press.

Referring now to FIG. 3 in conjunction with FIG. 1, the geometry and/ or radius of the top die 80 is selected which will govern the radius or geometry of the workpiece to be formed. Suitable replaceable dies 12 are selected having the appropriate radius of the round 14 for the desired geometrical shape of the piece to be formed. The distance between the bottom dies 12 are adjusted by loosening adjustable bolts 40 and moving first bases 32 along the slots 46. The workpiece 10 is subsequently placed on the top of the bottom dies 12 and cooling water or another cooling fluid is passed through the cooling manifolds 16, 28 and 54. Subsequently, the appropriate fuel-oxidant mixture is sent through the fuel-oxidant manifold 56 by adjusting the fuel valve 92 and oxidant valve 93 which are connected to the fuel supply tank 94 and oxidant supply tank 95, respectively. The fuel and oxidant are mixed and directed through a fuel-oxidant mixing and control valve 96 through line 97 to the fuel-oxidant manifold 5s and is ignited at the burner tips forming the flame 72. The flame 72 heats the workpiece 143 to the desired temperature which can be monitored by a thermocouple (not shown) connected to the workpiece it) or dies 12. By adjusting the fueloxidant valve 96 the heat intensity of the flame 72 can be controlled as a function of the thickness of the workpiece and the distance apart of the dies 12 allowing for forming a multitude of geometries with different size workpieces without the need for extensive retooling or hand working.

For most metal forming processes it is desirable to heat the workpiece to temperatures to 2500 F. without forming a carbon residue thereon. This can be accomplished by using a hydrogen-oxygen fuel mixture with the present invention. However, other fuel-oxidant mixtures which can be successfully used on various types of material workpieces are oxygen with either methyl, ethyl and furfuryl alcohols or with acetylene.

Referring to PEG. 3 whereon there is shown the workpiece fit on the bottom dies 12 prior to forming. The upper dies 30, which for purposes of example, is of a cylindrical geometry and capable of vertical movement as indicated by the arrow in FIG. 1, is propelled vertically downward by the conventional press brake (not shown) or other means, with sufiicient force F, to form the geometry of the upper die St in the workpiece 10 without breaking or cracking the workpiece it).

Referring now to FIG. 4 in conjunction with FIG. 1 there is shown the upper die 8th in contact with the workpiece ilZ during forming. The filets 98 in workpiece 10 are formed to the geometry of the round 14 in dies 12. After forming the refractory workpiece, the fuel-oxidant valve 96 is shut off and the workpiece It) is allowed to cool to room temperature.

The workpiece Id can be a tungsten sheet of a thickness ranging from approximately 0.005 to 0.1 inch. However, smaller or larger thickness refractory metal can also be formed. \Vith modifications of the die square bending and contour bending of other shapes can be obtained with the invention including oval cross sections where necessary.

While the invention described herein is described in detail in its present embodiments, it will be obvious to those skilled in the art after understanding the invention that various changes and modifications may be made therein without departing from the spirit or the scope thereof. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. Apparatus for forming a refractory or super alloy workpiece at an elevated temperature above 1600 F. with a minimum of hand working comprising a pair of spaced dies having rounds on the corners thereof for engaging the workpiece,

supports for holding the spaced dies,

a plurality of ribs in contact with said supports for providing convection cooling thereof,

a pair of bases attached to said ribs, each of said bases having a plurality of elongated slots therein,

a plate for engaging said pair of bases, said plate having a plurality of threaded holes therein aligned with said elongated slots in said bases,

a threaded member extending through each of said slots in said bases into said holes in said plate for holding said dies in a predetermined position,

a manifold centrally disposed in said plate between said bases,

a plurality of burner plugs in said manifold, each having a burner tip attached thereto,

means for supplying a hydrogen-oxidant mixture to said manifold,

control means for regulating the hydrogen-oxidant ratio and the flow rate of the mixture so that a .plurality of flames are directed from said burner tips against the lower surface of the workpiece to heat the same to elevated temperatures Without forming a carbon residue thereon,

means for circulating a liquid coolant through said manifold and spaced dies,

a forming die centrally located relative to the said plate above the workpiece, and

means for producing a force on said forming die to form the workpiece When the same has been heated to the elevated temperature.

2. Apparatus for forming a refractory or super alloy workpiece at an elevated temperature above 1600 F. with a minimum of handworking as claimed in claim 1 including means for circulating Water through the manifold and spaced dies.

3. Apparatus for forming a refractory 0r super alloy workpiece at an elevated temperature above 1600 F. with a minimum of handworking as claimed in claim -1 ineluding means for circulating a liquid coolant through the supports to maintain a constant temperature therein so that the dies are cooled by conduction.

4. Apparatus for forming a refractory or super alloy workpiece at an elevated temperature above 1600 F. with a minimum of handworking as claimed in claim 3 including means for circulating Water through the supports to cool the dies.

References fitted by the Examiner UNITED STATES PATENTS 1,487,839 3/1924 Claybourn 72--342 2,650,637 9/1953 Paxson 72--389 3,893,459 7/1959 Kosek 72342 CHARLES W. LANHAM, Primary Examiner.

L. A. LARSON, Assistant Examiner. 

1. APPARATUS FOR FORMING A REFRACTORY OR SUPER ALLOY WORKPIECE AT AN ELEVATED TEMPERATURE ABOVE 1600*F. WITH A MINIMUM OF HAND WORKING COMPRISING A PAIR OF SPACED DIES HAVING ROUNDS ON THE CORNERS THEREOF FOR ENGAGING THE WORKPIECE, SUPPORTS FOR HOLDING THE SPACED DIES, A PLURALITY OF RIBS IN CONTACT WITH SAID SUPPORTS FOR PROVIDING CONVECTION COOLING THEREOF. A PAIR OF BASES ATTACHED TO SAID RIBS, EACH OF SAID BASES HAVING A PLURALITY OF ELONGATED SLOTS THEREIN, A PLATE FOR ENGAGING SAID PAIR OF BASES, SAID PLATE HAVING A PLURALITY OF THREADED HOLES THEREIN ALIGNED WITH SAID ELONGATED SLOTS IN SAID BASES, A THREADED MEMBER EXTENDING THROUGH EACH OF SAID SLOTS IN SAID BASES INTO SAID HOLES IN SAID PLATE FOR HOLDING SAID DIES IN A PREDETERMINED POSITION, A MANIFOLD CENTRALLY DISPOSED IN SAID PLATE BETWEEN SAID BASES, A PLURALITY OF BURNER PLUGS IN SAID MANIFOLD, EACH HAVING A BURNER TIP ATTACHED THERETO, MEANS FOR SUPPLYING A HYDROGEN-OXIDANT MIXTURE TO SAID MANIFOLD, CONTROL MEANS FOR REGULATING THE HYDROGEN-OXIDANT RATIO AND THE FLOW RATE OF THE MIXTURE SO THAT A PLURALITY OF FLAMES ARE DIRECTED FROM SAID BURNER TIPS AGAINST THE LOWER SURFACE OF THE WORKPIECE TO HEAT THE SAME TO ELEVATED TEMPERATURES WITHOUT FORMING A CARBON RESIDUE THEREON, MEANS FOR CIRCULATING A LIQUID COOLANT THROUGH SAID MANIFOLD AND SPACED DIES, A FORMING DIE CENTRALLY LOCATED RELATIVE TO THE SAID PLATE ABOVE THE WORKPIECE, AND MEANS FOR PRODUCING A FORCE ON SAID FORMING DIE TO FORM THE WORKPIECE WHEN THE SAME HAS BEEN HEATED TO THE ELEVATED TEMPERATURE. 